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MySQL databases are relational.

A relational database Stores data in separate tables rather than putting all the data in one big

storeroom. The database structures are organized into physical files optimized for speed. The

logical model, with objects such as databases, tables, views, rows, and columns, offers a flexible

programming environment. You set up rules governing the relationships between different data

fields, such as one-to-one, one-to-many, unique, required or optional, and “pointers” between

different tables. The database enforces these rules, so that with a well-designed database, your

application never sees inconsistent, duplicate, orphan, out-of-date, or missing data. The SQL part of “MySQL" stands for “Structured Query Language". SQL is the most co m mon

standardized language used to access databases. Depending on your programming environment,

you might enter SQL directly (for example, to generate reports), embed SQL statements into codę

written in another language, or use a language-specific API that hides the SQL syntax.

ŚQL is defined by the ANSI/ISO SQL Standard. The SQL standard has been evolving sińce 1986

and several versions exist. In this manuał, “SQL-92” refers to the standard released in 1992,

“SQL:1999” refers to the standard released in 1999, and “SQL:2003” refers to the current version

of the standard. We use the phrase “the SQL standard" to mean the current version of the SQL Standard atanytime.